Quenching oil composition

ABSTRACT

A quenching oil composition for simultaneously hardening ferrous metals and imparting excellent cleanliness or brightness to the metal surface and comprises a major portion of a mineral oil with high heat-exchange rate containing a minor proportion of an ashless mono(polyisobutenyl) succinimide.

United States Patent [1 1 Wilpers [52] US. Cl. 148/29; 148/206; 252/77 {51] Int. Cl. C21D 1/44 [58] Field of Search 148/27, 28, 29, 20.6, 143; 252/71, 74, 75, 76, 77

[56] References Cited UNITED STATES PATENTS $224,910 12/1965 MCEwen 148/143 Dec. 9, 1975 3.272361 9/1966 Riggs 148/28 3.281.288 10/1966 Carver et a1 148/206 3.853.638 12/1974 Wilpers 148/29 3,866,603 2/1975 Wilpers w. 148/206 Primary Examiner-Waiter R. Satterfield 1 1 ABSTRACT A quenching oil composition for simu1taneous1y hardening ferrous metals and imparting excellent cleanliness or brightness to the metal surface comprises a major portion of a mineral oil with high heatexchange rate containing a minor proportion of an ashless mono( po1yisobutenyl) succinimide.

4 Claims, No Drawings QUENCHING OIL COMPOSITION This is a division of application Ser. No. 42 .204. filed Dec. 21. I973, non USv Pat. No. 3.866.603.

BACKGROUND OF THE INVENTION The method of hardening ferrous materials by heating them to a temperature above 1,600F and then tap idly cooling them in order to increase the hardness is well known. The cooling step in this procedure is 1 termed quenching. It is also known that an increase in the speed of quenching results in increased metallic hardness. Hydrocarbon oils, in particular mineral oils, are commonly used as quenching liquids. A few mineral oils naturally have a high heat-exchange rate and can be used as is for quenching oils. But in general straight mineral oils do not usually form satisfactory quench media since the initial rate of cooling is too slow. It has been assumed that the widely different quenching speeds between a few and most oils is due to presence or absence of compositional components in very small concentrations. Hence, the development of the quenching oil art has been in the direction of modifying hydrocarbon oils by incorporating certain additives therein. The state of the art is such that many various different additives have been used for this purpose; see, for example, U.S. Pat. No. 3,729,417, issued Apr. 24, 1973. Illustrative of these additives for improving cooling rate are ash-forming materials such as oil-soluble alkali metal and/or alkaline earth metal petroleum sulfonates, e.g., calcium, sodium, or barium sulfonates. Such materials leave behind on the metal an ash or deposit which affects the brightness or cleanliness of the metal surface. These deposits are difficult to wipe off or remove from the metal surface. The two most important aspects of quenching oil performance are hardening ability and cleanliness of quenched metal surface. The problem is that high-speed quenching oils, which have good hardening ability, usually produce unclean or stained metal surfaces. In one solution to the problem, copending application U.S. Ser. No. 373,065 now U.S. Pat. No. 3,853,638, filed June 25, I973, discloses an oil composition which contains an effective additive that facilitates rapid heat exchange between the metal and the oil composition in the heat treating process, such as the hardening of steel, and which leaves on heat-treated metal surfaces an easily removable flaky deposit. However, it would be an advance in the art o provide a high-speed quenching oil composition capable of producing bright quenched ferrous metal surfaces.

SUMMARY OF THE INVENTION It has now been found that a non-staining, i.e., bright high-speed quenching oil consists essentially of a mineral oil having a high heat exchange rate as measured by a GMC Magnetic Quenchometer Time of from about 9 to about seconds which contains dissolved therein a minor amount within the range of from about 0.l to about 10 percent by weight of a critically specific detergent-type composition. The specific detergenttype component required for the non-staining quenching oil composition of the invention is a mono( polyisobutenyl)-substituted succinimide of tetraethylenepentamine. An improved method for quenching metals, especially steel, is obtained by use of the abovcdefined quenching oil.

' polyisobutenyll-substituted DESCRIPTION OF THE PREFERRED EMBODIMENTS The mineral oil base, which in addition to the additive is a critical feature of the invention, must have not only thermal and oxidative resistant properties capable of meeting the requirements desired in a quenching oil, but also must possess a high heat-exchange rate. The high heat-exchange rate required by the mineral oil 0 component of the composition of the invention can be indicated by or defined in terms of quenching time as measured in the GMC Magnetic Quenchometer Test. This test takes advantage of the fact that metals lose their magnetic properties when heated above a critical temperature called the Curie point" and regain it when cooled. Polished nickel balls, preheated to l,625F in a muffle furnace, are dropped past a photoelectric cell into a measured volume of oil located in a magnetic field. When the nickel ball cools to its Curie point, approximately 670F for pure nickel, it regains its magnetic properties and is drawn to a magnet. An electric timer, which is engaged when the nickel ball passes the photoelectric cell, is automatically stopped when the ball is drawn to the magnet. The recorded time in seconds is reported as the quenching time of the sample or oil being tested. The lower the quenching time reported, i.e., the smaller the number of seconds, the faster is the speed of the quenching oil and the greater its cooling effectiveness. For the purposes of the composition of the invention the mineral oil component must possess a quenching time in the range of from about 9 to about 15 seconds as measured in the above-described GMC Magnetic Quenchometer Test. Oils which possess a quenching time in this range are high-speed quenching oils. As mentioned previously a few mineral oils naturally have a high heat-exchange rate and can be used as is for the high-speed quenching mineral oil component of the composition of the invention. Also useful as the mineral oil component of the composition of the invention are certain mineral oils containing ashless additives to improve the quench speed thereof such as disclosed in the above-mentioned copending application U.S. Ser. No. 373,065 now U.S. Pat. No. 3,853,638, filed June 25, 1973, wherein is disclosed quenching oil with an improved rate of cooling consisting essentially of a mineral oil having a viscosity of from about 15 to about 200 SUS at l00F and an aromatic content of 8 to 60% which contains dissolved therein a critical amount within the range of from about 0.005 to about 0.04 percent by weight of a vicinal dihydrocarbyl-substituted 2-mercaptothiazole, each hydrocarbyl being preferably of l to 6 carbon atoms. In summation, the mineral oil component of the composition of the invention may be a high-speed quenching mineral oil alone or a high-speed quenching mineral oil containing additives to improve the quench speed of the mineral base oil such that, in all cases, the mineral oil component of the invention as so exemplified above has a quenching time of from about 9 to about 15 seconds as measured in the GMC Magnetic Quenchometer Test.

The critically specific detergent-type component required for the non-staining quenching oil composition of the invention may be defined as a mono(- succinimide of tetracthylenepentamine wherein the molecular weight of the polyisobutenyl substitutent is from about 700 to about 5.000 and preferably from about 2,000 to about 4.000.

contain the above-defined mono(polyisobutenyl) sucl cinimide additive, can be further improved with respect to oxidation stability by addition thereto of phenolic antioxidants, amine antioxidants and the like.

EXAMPLE I 1 5 The mineral oil component alone and the mineral oil component together with the indicated concentration of additive given below and the effectiveness thereof as non-staining high-speed quenching oils is demonstrated by testing the compositions in the GMC Magnetic Quenchometer Test. This test has been described hereinabove for the determination of the speed of quenching time. The test is also determinative of the quenched metal surface brightness or non-staining effectiveness of a quenching oil composition in the following manner. The polished nickel balls used in the determination of the quenching time (GMC Quenching Time, seconds) are given a cleanliness rating, after the quenching time is obtained, which is determined by the appearance of the quenched nickel balls. The cleanliness or brightness rating is indicative of the non-staining effectiveness of the quenching oil composition and the rating is expressed as a letter from A" through E" inclusive where the letter rating is defined as follows:

A zero to trace deposits B= trace to light deposits C= light deposits D moderate deposits E= heavy deposits.

In actual commercial quenching operations, the quenching oil is kept in motion or stirred during the quenching and, subsequently, quenched metal parts are often washed or wiped to remove residual oil. To more adequately reflect commercial operation and obtain results more reflective of the effectiveness of the additive in achieving brightness or non-staining of the metal, a modification step subsequent to the abovedescribed GMC Magnetic Quenchometer Test has been devised for use in conjunction therewith. The modified test consists of dropping a standard GMC Magnetic Quenchometer test ball (i.e., a polished nickel ball) preheated to l,625F in a muffle furnace, into 260 grams of quenching oil to be tested and stirring the oil rapidly for 15 minutes. The ball is then letter rated for surface deposit by the above-defined letters ranging from A through E. Next the ball is wiped with a towel and letter rated again. In Table 1 below, run 1 gives data and results from the mineral oil component alone without detergent-type additive; runs 2 and 3 indicate the effectiveness of the additive compositions of the invention; and runs 4 through 7 containing additives not according to the invention are included to show how additives of similar detergent type or similar chemical content are far less effective than the compositions of the invention in high-speed, nonstaining quenching of metal. The mineral oil component used as base oil in Table I below has the following composition:

In volume weight (-47 SUS at [00F) loriol" antioxidant 0.25 (2.6-diterL-butyl-4- methylphenol) Table l Run Base oil alone Test Oil Modified Telt Quenched Metal Surface Brightness Before After Wiping Wiping GMC Magnetic Quenchometer Test Quenching Quenching Time Metal Surface (sec) Brightness ll.8 D D D 12.0 C B A Base oil 5%: of mono(polyisobutenyl) luccinimide of tctraethylenepentamine; moLwt. polyisobutenyl group within range of from about 700 to about ll.9 C

ll.4 C

ll.2 D

Table l-contmued GMC Magnetic Modified Test Quenchometer Test Quenched Metal Quenching Quenching Surface Brightness Time Metal Surface Before After Run Test Oil (sec) Brightness Wiping Wiping polyisobutenyl succinic acid diester of a polyol 7. Base oil 57zw of l3.3 D D D Mannich base (aldehyde-amine) detergent containing about 043%; boronv I claim as my invention: 15

l. A non-staining quenching oil composition consisting essentially of a mineral oil, having a high-heat exchange rate as measured by a magnetic quenchometer time of from about 9 to about 15 seconds, and from about 0.1 to about 10 percent by weight of a mono(- polyisobutenyl)-substituted succinimide of tetraethylenepentamine wherein the polyisobutenyl substituent has a molecular weight of from about 750 to about 5,000.

2. The composition of claim 1 wherein the mineral oil with high-heat exchange rate is a mineral oil, having a viscosity of from about to about 200 SUS at l00F and an aromatic content of from 8 to 60 percent, which contains from about 0.005 to about 0.04 percent by weight of a vicinal dihydrocarbyl-substituted Z-mercaptothiazole, each hydrocarbyl substituent having from 1 to 6 carbon atoms.

3. The composition of claim 1 wherein said succinimide is present in an amount of from about 0.5 to about 5 percent by weight.

4. The composition of claim 1 wherein said polyisobutenyl group has a molecular weight of from about 2,000 to about 4,000. 

1. A NON-STAINING QUENCHING OIL COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL OIL, HAVING A HIGH-HEAT EXCHANGE RATE AS MEASURED BY A MAGNETIC QUENCHOMETER TIME OF FROM ABOUT 9 TO ABOUT 15 SECONDS, AND FROM ABOUT 0.1 TO ABOUT 10 PERCENT BY WEIGHT OF A MONO(POLYISOBUTENYL)-SUBSTITUTED SUCCINIMIDE OF TETRAETHYLENEPENTAMINE WHEREIN THE POLYISOBUTENYL SUBSTITUENT HAS A MOLECULAR WEIGHT OF FROM ABOUT 750 TO ABOUT 5,000.
 2. The composition of claim 1 wherein the mineral oil with high-heat exchange rate is a mineral oil, having a viscosity of from about 15 to about 200 SUS at 100*F and an aromatic content of from 8 to 60 percent, which contains from about 0.005 to about 0.04 percent by weight of a vicinal dihydrocarbyl-substituted 2-mercaptothiazole, each hydrocarbyl substituent having from 1 to 6 carbon atoms.
 3. The composition of claim 1 wherein said succinimide is present in an amount of from about 0.5 to about 5 percent by weight.
 4. The composition of claim 1 wherein said polyisobutenyl group has a molecular weight of from about 2,000 to about 4,000. 